This invention relates to microscopes in general and more particularly, to apparatus for increasing the light input to a microscope.
Generally speaking, the amount of light available in a microscope determines the clarity with which the image is viewed and for exacting work such a microscope should preferably provide the user with a clear image at optimum intensity. A particular problem exists in the use of the so-called "operation microscopes" or those devices used by surgeons and physicians to aid in performing delicate surgical procedures. The use of such microscopes in consistent with a desire to provide increased illumination at the object plane as above indicated and is coupled with the further problem of reducing heat in the area of the device.
In general, a surgical or operating room microscope is draped or covered during an operation to maintain a sterile environment and to allow the physician to concentrate on the area of the patient he is operating on. Such microscopes as used in the prior art contain additional lamp assemblies or housings which include high intensity and high power lamps. The light from the lamp is directed into the optical path of the microscope by means of lenses or prisms to increase illumination. Such devices are coupled to the body of the microscope by means of a suitable housing and become part of the microscope assembly. As such, these housings are also draped during surgery and the associated lamps severely increase the ambient temperature within the surgical draping canopy. Due to the increased heat, the additional lamp source is subjected to a relatively high failure rate and such a failure will necessitate the replacement of the lamp during a surgical procedure at great expense in time and effort. As one can imagine, time is of the essence in an operative procedure and such results could jeopardize the patient.
Hence, the prior art attempted to inject additional light into the optical path of the microscope by using fiber optic cables to conduct light from a remote source. Most of these attempts were unsuccessful as the light so injected served to distort the depth of field of the microscope and hence, unduly affected the surgeon's field of view during an operation.
Furthermore, the use of fiber optics employed prisms to bend or angle the light and resulted in a loss of intensity, which limited the amount of the additional light introduced.
The major desire of such apparatus is to introduce additional light into the optical path of a conventional microscope without affecting the design of the instrument or its operating characteristics. Such microscopes are in widespread use and are relatively expensive and quality devices. Physicians rely on the characteristics of such microscopes and are familiar with their operation and adjustments.
An example of a particular successful instrument is the OPMI 1 microscope manufactured by the Carl Zeiss Company of West Germany. This particular instrument has provisions for increasing the light in the microscope by providing a lamp housing assembly which is coupled to the body of the scope. As above indicated, this housing is associated with and provides large amounts of heat which result in the above noted difficulties.
Also in regard to such operating room microscopes is the requirement that additional light is further desirable because of additional attachments which may be necessary to to monitor the progress of the operation. For example, operating room microscopes have provisions for attaching additional apparatus to the body of the microscope so that the physician may photograph the area by the use of a 35 millimeter camera or a television monitor may be coupled to the microscope to monitor the progress of the operation. Such attachments such as a television or 35 millimeter camera require more light.
It is, of course, understood that the apparatus for increasing the light input to a microscope should also do so by internal means. External lights of course, can be used to illuminate the operating area but they serve to decrease the physical distance from the objective lens of the microscope to the object plane. This becomes a real problem for the surgeon because by doing this, one alters the physical difference between the bottom of the microscope and the area he is viewing and hence, gives the surgeon less space in the operating area. Therefore, a surgeon prefers an internal illumination scheme over an external system because of the additional space required.
It is therefore an object of the present invention to increase the amount of light in a microscope without unduly affecting the operation of the device and without providing additional heat in the immediate area of the microscope.